Laser-assisted in situ keratomileusis posterior ablation platform

A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery.     

Laser-assisted subepithelial keratectomy retreatment after laser in situ keratomileusis

PURPOSE: To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy (LASEK) retreatment after laser in situ keratomileusis (LASIK). SETTING: Mater Private Hospital, Dublin, Ireland. METHODS: In this retrospective study, 22 eyes of 20 patients had LASEK retreatment for residual refractive errors after LASIK. All patients who had the procedure between January 2004 and May 2007 were included in the study. The main outcome measures at the final follow-up visit were efficacy, predictability, safety, and stability. RESULTS: The mean spherical equivalent (SE) was -4.50 diopters (D)+/-2.88 (SD) (range -10.00 to +3.87 D) before LASIK and -1.23+/-0.95 D (range -2.50 to +2.00 D) after LASIK. The mean time between the initial LASIK procedure and LASEK enhancement was 56.2+/-24.3 months (range 6 to 84 months). The mean follow-up after retreatment was 6.68+/-6.47 months (range 3 to 24 months). At the final follow-up visit, 19 eyes (86.4%) had an uncorrected visual acuity of 20/30 or better and 17 eyes (77.3%) were within +/-1.00 D of the target refraction. No patient lost more than 1 line of best corrected visual acuity or developed corneal haze greater than grade 1. CONCLUSION: Results indicate that LASEK retreatment after LASIK is a safe and effective alternative when LASIK retreatment is deemed unsafe because there is not sufficient residual corneal stromal bed or when retreatment is required many years after LASIK and relifting the original flap is expected to be problematic.     

Postoperative complications in laser in situ keratomileusis

Laser in situ keratomileusis (LASIK) has become the most common procedure to correct refractive errors in North America. Increasing numbers of patients and surgeons are choosing LASIK in the management of low and moderate myopia, astigmatism, and hyperopia. LASIK presents a unique group of postoperative challenges and complications. It is important to be able to identify these complications in the early and late postoperative periods and to provide effective management. In this article, we review the most commonly encountered early and late postoperative complications after LASIK and the most current methods in prevention and treatment.     

Microkeratome complications of laser in situ keratomileusis

PURPOSE: To evaluate the incidence, types, and outcome of microkeratome complications that occur during laser in situ keratomileusis (LASIK). DESIGN: Retrospective, noncomparative, case series. PARTICIPANTS: Three thousand nine hundred ninety-eight eyes that underwent primary LASIK by four surgeons between November 1996 and August 1998 at a university-based refractive center. METHODS: All cases with significant microkeratome complications leading to abandonment of the LASIK procedure were identified and reviewed. MAIN OUTCOME MEASURES: Incidence of complications, change in best corrected visual acuity (BCVA), change in refractive error, and types of complication. RESULTS: There were 27 complications leading to abandonment of the LASIK procedure of 3998 eyes. The overall rate of microkeratome complication was 1 in 150 (0.68%), but it was 1 in 77 (1.3%) in the surgeons' first 1000 eyes, decreasing to 1 in 250 (0.4%) in the last 1000 eyes. Of the 24 planned bilateral cases, 15 complications (63%) happened on the first operated eye. Twenty-six of 27 eyes (96%) recovered to within one line of preoperative BCVA, and one eye lost two lines. At last examination before any repeat refractive procedures, spherical equivalent manifest refraction returned to within 1 diopter (D) of its preoperative value in 18 of 19 eyes (95%), and astigmatism in 16 of 19 eyes (84%) returned to within 1 D of its preoperative value. Sixteen of 27 eyes (59%) had repeat LASIK. Two eyes had complications at repeat LASIK, one of which led to abandonment of the LASIK procedure for a second time. CONCLUSIONS: There is a significant learning curve in the use of the microkeratome. If ablation is not performed, flap complications rarely lead to significant visual loss and generally do not result in a change in refractive error.     

Laser in situ keratomileusis in patients with diabetes

PURPOSE: To study the outcomes of laser in situ keratomileusis (LASIK) in patients with well-controlled diabetes mellitus. SETTING: Gimbel Eye Centres, Calgary and Edmonton, Canada. METHODS: The charts of all patients with diabetes who had LASIK surgery at the Gimbel Eye Centres were reviewed retrospectively. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), final refraction, and complications were assessed. RESULTS: Twenty-four patients (16 men and 8 women) were identified. Mean patient age was 42 years (range 24 to 57 years). Seventeen patients had diabetes type II, and 7 had diabetes type I. Mean preoperative spherical equivalent (SE) was -4.88 +/- 2.13 diopters (D) (range +1.625 to -9.00 D). Median follow-up was 6 months (range 4 to 44 months). No eye lost BSCVA. Twenty-nine eyes (63%) achieved UCVA 20/25 or better, and 31 eyes (67%) were within +/-0.5 D of the intended refraction after the first LASIK surgery. Retreatment was required in 13 eyes (28.3%) because initial surgery was not adequate to correct the refractive error. At the last follow-up visit, 40 eyes (87%) achieved UCVA of 20/25 or better and 43 eyes (93.5%) were within +/-0.5 D of the intended refraction. Three eyes (6.5%) developed an epithelial defect after surgery, and secondary epithelial ingrowth developed in 2 of these eyes. No advancement of diabetic retinopathy was noticed in any eye at the end of the follow-up period. CONCLUSIONS: Laser in situ keratomileusis surgery was safely performed in patients with well-controlled diabetes. Enhancement may often be required for optimal correction.     

Laser of complications in in situ keratomileusis (LASIK)

Background: The incidence and course of intraoperative and postoperative complications of LASIK were investigated. Patients and methods: We consecutively treated 598 eyes (316 patients) using the Automatic Corneal Shaper and the Keracor 117 C excimer laser. One hundred and sixty-three eyes were also available at 12 months. The preoperative spherical equivalent was − 5.31 ± 5.49 D (+ 9 to − 23 D). We evaluated intra- and postoperative complications. Results: Intraoperative complications of keratotomy were observed in 1.3 % (irregular cut, n = 5; free cap, n = 2; incomplete cap, n = 1), and other intraoperative complications in 1.7 % (epithelial defects, n = 7; flap dislocation, n = 1; lateral kanthotomy required, n = 2). None of these complications caused any long-term effects or loss of two or more lines of visual acuity. Postoperative complications were observed in 0.9 % (peripheral epithelial ingrowth, n = 4; keratectasia, n = 1; subretinal neovascularisation, n = 1). Conclusions: The rate of complications in LASIK is low, and intraoperative complications did not cause any significant loss of vision. We observed keratectasia in one eye, which suggests that deep ablations should be avoided, which limits the amount of correction possible.      

准分子激光角膜上皮瓣下磨镶术矫正超高度近视

目的探讨准分子激光上皮瓣下角膜磨镶术(laser-assisted subepithelial keratomileusis,LASEK)矫治超高度近视的安全性及有效性。方法选择2007年1月至2009年12月在我院行LASEK的超高度近视患者151例(302眼),按近视程度进行分组:Ⅰ组(-10.00～-12.00D)174眼,Ⅱ组(-12.25～-16.00D)128眼。术后随访超过12个月,观察术后眼部反应、角膜愈合、裸眼视力、等效球镜、haze、眼压等情况。结果术后12个月裸眼视力≥1.0者Ⅰ组148眼(85.1%),Ⅱ组70眼(54.7%),差异有显著统计学意义(χ2=33.878,P=0.000);术后发生0.5～Ⅰ级Haze者Ⅰ组5眼(2.9%),Ⅱ组6眼(4.7%),差异无统计学意义(χ2=0.691,P=0.406),经3～6个月治疗均低于0.5级。眼压升高需药物控制者Ⅰ组36眼(20.7%),Ⅱ组37眼(28.9%),差异无统计学意义(χ2=2.716,P=0.099)。术后3个月、6个月、12个月等效球镜组间比较,差异均有统计学意义(P<0.05或0.01)。结论 LASEK可矫正超高度近视,但务必监测眼压以防止激素性青光眼的发生。     

LASEK治疗LASIK术后屈光异常的临床研究

目的探讨准分子激光原位角膜磨镶术(LASIK)后屈光异常(屈光回退、欠矫、过矫)行准分子激光角膜上皮瓣下磨镶术(LASEK)治疗的可行性及临床疗效。方法对45例(77只眼)行LASIK治疗后所致的屈光异常患者,均在原角膜瓣上行LASEK治疗。其中屈光回退26例(47只眼),欠矫13例(19只眼),过矫6例(11只眼)。术中制作角膜上皮瓣时,环形角膜上皮锯仅做垂直向下的轻压动作,20%酒精脱角膜上皮的时间为18-25秒。术后观察眼部刺激症状,角膜上皮瓣及角膜基质反应,视力,屈光度改变,角膜Haze,屈光回退,术后并发症等情况。随访时间均≥6个月。结果术后眼部刺激症状较轻,角膜上皮瓣对位复贴良好,角膜上皮瓣轻度水肿一般3天消失,未见明显角膜基质反应,视力于术后9-14天即可达最佳矫正视力,术后6个月平均屈光度为( 0.25±0.32)D,术后角膜Haze发生率较少,未发生屈光回退、激素性高眼压及继发性圆锥角膜。结论LASEK治疗LASIK术后屈光异常安全可行,疗效确切,远期疗效有待进一步观察。     

Retinal complications after laser-assisted in situ keratomileusis (LASIK)

PURPOSE OF REVIEW: This paper reviews the retinal complications that may occur after laser-assisted in situ keratomileusis (LASIK). RECENT FINDINGS: During the review period (1 year), several nonrandomized retrospective studies and case reports/series were published. One study was performed to determine the efficacy and safety of prophylactic laser photocoagulation for retinal breaks in patients with myopia undergoing LASIK. Retinal breaks were identified and treated in 39 eyes (2%). None of the patients developed a rhegmatogenous retinal detachment (RRD) (except one trauma case). Another group studied retinal disease observed in 9239 consecutive eyes after refractive surgery (including LASIK) and found RRD in 11 eyes (0.36%) and choroidal neovascularization (CNV) in 10 eyes (0.33%). Three reports described a total of 16 patients with a previously placed encircling scleral buckle for a RRD who had LASIK to correct myopia. In all patients, the visual acuity (VA) improved. Another study reported the characteristics and surgical outcomes of RRD in myopic eyes after LASIK (33 eyes of 27 patients; frequency 0.08% [33/38, 823]). They found that 45.8% lost two or more lines of VA after vitreoretinal surgery. Two letters described the characteristics and potential mechanisms of a macular lacquer crack (one with subsequent development of subfoveal CNV) in a myopic patients corrected by LASIK. SUMMARY: Serious complications after LASIK are infrequent. A dilated fundus examination is very important before LASIK and in every patient whose VA after LASIK is not as good as expected to avoid delayed referral to a vitreoretinal specialist if necessary. Only prospective studies can determine whether the procedure exacerbates myopic pathology.     

飞秒激光制瓣技术的优势与相关并发症

角膜屈光手术引入飞秒激光制作角膜瓣已经有十年的历史,设备从原先的高脉冲能量低频率逐渐转变为当前的低脉冲能量高频率。与传统的机械式显微角膜板层切开刀相比,飞秒激光具有一定的优势,如制做准分子激光原位角膜磨镶术（LASIK）角膜瓣厚度精确、均匀,术中无角膜瓣破碎等严重并发症;可以个性化地设计角膜瓣形状、大小以及边切角度。也有利用飞秒激光进行角膜透镜切除,即全飞秒激光矫正近视及散光的方法。但飞秒激光也有其特殊的术中及术后并发症,如激光制瓣过程中负压丢失、纽扣瓣、不透明气泡层、彩虹症及光敏综合征等。我们对此要有正确客观的认识,随着设备技术的改进与操作经验的积累,不断提高角膜屈光手术的疗效以及患者的满意度。     

Incidence of intraoperative flap complications in laser in situ keratomileusis.

PURPOSE: To evaluate the incidence of intraoperative flap complications in laser in situ keratomileusis (LASIK) and compare the incidence between eyes and between the Hansatome and Automated Corneal Shaper (Bausch & Lomb) microkeratomes. SETTING: Open-access outpatient excimer laser surgical facility. METHODS: A retrospective analysis was done of 84711 primary LASIK cases performed between November 1998 and May 2000 in 28 national open-access laser facilities. The intraoperative flap complications were identified and categorized into type of complication, eye involved, and microkeratome type. All cases used the Automated Corneal Shaper or the Hansatome microkeratome. RESULTS: Two hundred fifty-six complications (0.302%) were identified: 29 failures to achieve intraocular pressure (0.034%), 84 partial flaps (0.099%), 59 buttonholes (0.070%), 74 thin or irregular flaps (0.087%), and 10 free flaps (0.012%). There were 134 right eye complications and 122 left eye complications (P =.45). No patient developed an intraoperative flap complication in both eyes. A comparison of Hansatome and Automated Corneal Shaper microkeratomes was possible for the cases performed between December 1999 and May 2000: 46 of 28 201 Hansatome procedures (0.16%) had a complication versus 21 of 329 Automated Corneal Shaper procedures (6.38%). This difference was statistically significant (P <.005). CONCLUSION: The incidence of intraoperative flap complications during LASIK was acceptably small. The overall complication rate was similar in both eyes. The Hansatome was associated with a lower complication rate than the Automated Corneal Shaper.     

LASIK手术并发症对眼波阵面像差的影响

目的　探讨屈光手术后中央岛、偏中心、不规则散光、多中心切削等并发症对眼波阵面像差的影响。方法　进行一项回顾性的临床研究 ,对接受 L ASIK手术术后发生各种并发症的 2 5例患者 (2 9只眼 )的眼波阵面像差进行了评估。采用主观性波阵面像差仪对眼波阵面像差进行了测量与比较。检查结果通过 Madlab软件分析 ,直接获取 35项 Zemike系数及每阶 Zemike系数的 RMS值。结果　无并发症组患者术前最佳矫正视力 (BCVA)是 1.0 1± 0 .12 ,术后 3月 BCVA为 0 .99± 0 .14 ;并发症组患者术前 BCVA是 1.0 2± 0 .0 9,术后 BCVA为 0 .6 1± 0 .2 4。术前眼波阵面像差的 RMS值为 0 .6 5μm ,术后无并发症组为 1.5 1μm;而中央岛组的 RMS值为 6 .78μm ;偏中心组为 7.94μm;不规则散光组为 9.32μm ;多中心切削组为 7.2 9μm。结论　 L ASIK术中术后所致的并发症可导致眼波阵面像差数倍的增加 ,严重影响患者术后的视觉质量     

准分子激光原位角膜磨镶术后并发症临床分析

目的:分析LASIK术后并发症,探讨其处理方法。方法:应用visx-star4准分子激光机对1000例1928眼做LASIK手术,术后随访6mo。结果:术后并发症有角膜层间异物残留、眩光、屈光度欠矫或过矫、不完全角膜瓣、游离瓣、视疲劳、沙漠综合征、复发性角膜上皮剥脱、高眼压症等。结论:LASIK治疗近视安全、有效,但存在一定的并发症,必须引起重视。手术技巧的提高和手术设计的完善,有助于减少手术并发症的发生和提高手术的预测性和准确性。